In order to more fully understand the nature of the present invention, it is necessary to understand that high explosive materials can be classified into two major groups: initiating or primary explosives, and non-initiating or secondary explosives. The present invention is specifically directed to the initiation of secondary explosives, which materials include PETN (pentaerythritotetranitrate), RDX (cyclotrimethylene trinitramine, and HMX (cyclotetramethylene tetranitramine) and any other of that explosive class which may or may not be blended with a material to improve its sensitivity to initiation by laser energy. The direct initiation of secondary explosives by laser energy transmitted through a fiber optic has heretofore required high laser energy levels to effect highly reliable initiation thereby requiring larger and more expensive laser light sources while limiting the range of application and use of such devices. PCT publication W088/07170 shows an optic detonator wherein fiber optics are used for igniting a mixture of gases such as hydrogen and chlorine; U.S. Pat. No. 4,892,037 is typical of initiation devices using primary explosives with fiber optics in physical contact with or imbedded in the consumable material so as to create a self-consumable initiator; hence U.S. Pat. No. 4,892,037 is silent as to the utilization of any teaching relating to secondary explosives. Similarly, in U.S. Pat. No. 3,408,937, the utilization of a light initiated explosive is clearly disclosed, but the inventor states that the explosive 13 is a pyrotechnic and the explosive device 11 is of no particular concern to the designer. The above listed prior art fails to disclose low energy fiber optic initiation of a secondary explosive.
A better understanding of the objects, advantages, features, properties and relations of the invention will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments and are indicative of the various ways in which the principles of the invention are employed.
It is a primary object of this invention to permit laser initiation through fiber optics of secondary explosives with an improved structure requiring significantly lower laser energy;
It is another object of this invention to provide an economical, easily fabricated laser initiation secondary explosive containing structure that provides high reliability of initiation.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.